Why are index fossils useful to geologists?

Question

A. They tell the age of the rock at one location only.

B. They tell the absolute age of the rock in which they occur.

C. They tell the relative age of the rock in which they occur.

D. They tell the ages of many different rock layers.

Answer 1

I think it's D
because Index fossils are used by both geologists and paleontologists to study the rocks and species of the past. They help to give a relative age for the rock layers and other fossils found in the same layer.